Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Brief description of components: Notes
The system features the following switches and sensors:
- Seat adjustment buttons
The seat adjustment buttons are located on the outer sides of the seat cushions. They vary in terms of number and function. The E64 seat is additionally equipped with an option for electrically adjusting the head restraints (headrests).
- Lumbar support button
A rocker switch is provided on the seat to adjust the lumbar support.
- Seat memory button
Only the driver's seat features additional buttons for the seat memory.
- Seat heating switch
The buttons for controlling the seat heating are included in the center console switch cluster.
- Hall sensors
Hall sensors are installed for the purpose of detecting the position of the seats. The sensors are integrated in the seat drive units.
- Temperature sensor for seat heating
A temperature sensor is installed in each of the seat cushions for the seat heating.
The seats are controlled by the following control units:
- Centre console switch cluster
In addition to the switches, the electronic circuits for the heating control and monitoring functions are integrated in the center console switch cluster (SZM). The SZM is also responsible for the electronic control of the steering column adjustment function.
For more information, refer to E63/E64 CENTRE CONSOLE SWITCH CLUSTER .
- E63/E64 Driver's seat module
The control unit of the driver's seat module (SMFA) communicates via the K-bus with the center console switch cluster (SZM).
- Passenger's seat module, E64 only
The control unit of the passenger's seat module (SMBF) communicates via the K-bus with the center console switch cluster (SZM). In the E63 the drive units are controlled directly by a load circuit.
The following actuators are driven to perform the seat functions:
- Seat heating
The seat cushion heating and backrest heating are installed such that they cover the entire area. Even the side sections and thigh supports are heated:
For more information, refer to E63/E64 SEAT HEATING .
- Seat adjustment drive units
The following drive units are installed in the E63 and E64 seat:
- Drive unit for seat forward/backward adjustment with 2 adjustment speeds
- Drive unit for seat height adjustment
- Drive unit for seat cushion tilt adjustment
- Drive unit for backrest angle adjustment
Additionally installed in the E64:
- Drive unit for head restraint height adjustment
- Head restraint angle adjustment
The head restraint angle adjustment as well as the seat depth adjustment on the sports seat are always manual.
- Lumbar support
The lumbar support in the seat backrest consists of 2 lumbar cushions as well as an electric air pump with electrically operated valves.
The following displays provide seat status information:
- Central Information Display
A corresponding check control message is shown on the central information display (CID) when, for example, a backrest is not locked in correctly (E64 only).
- Head-up display
A corresponding check control message and an information text are shown in the head-up display (HUD) when the backrest is not locked in correctly (E64 only).
- Seat heating LEDs
3 light emitting diodes (LEDs) in the center console switch cluster indicate the switched status of the seat heating system.
Seat communication features the following bus systems:
- Body controller area network
The body controller area network (K-CAN) is a two-wire bus for communication between all control units connected to the K-CAN.
- Body bus
The body bus (K-bus) is a single-wire connection. The center console switch cluster and the seat modules communicate with each other via the K-bus.
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.